1. Field of the Invention
This invention relates generally to cutting guides and blocks for bone preparation of a femur and, more particularly, distal cutting guides for preparation of the distal portion of the femur.
2. Related Art
In preparing the knee for implantation of a prosthesis in knee replacement surgery (either total knee replacement or partial knee replacement), the distal femur requires cuts on the bone in precise locations and precise planar angles. In many instances, the first cut may be a distal cut on the femur. Further cuts, including anterior, posterior, and any intermediate angled cuts, may be referenced from the distal cut. Thus, the distal cut may be used to orient all other cuts on the distal portion of the knee. Properly aligning the distal cutting block prior to making the distal cut may create a better fit and better performance of knee prosthesis.
Fixation of the cutting block to the femur has been accomplished by intramedullary (IM) rods or by pinning the guide to the femur. The IM rod may also be used as an alignment guide to orient a distal cutting guide. However, a surgeon does not align the cutting block perpendicular to the IM canal (the anatomical axis of the femur). Instead, the surgeon may align to a default angular offset that is built in to the cutting guide and is fixed within the cutting guide. Thus, if the surgeon desires to adjust the angle between the IM canal and the cutting guide (which affects the varus/valgus angle between the femur and tibia) then a different cutting block may be required having a different fixed cutting guide orientation. Additional cutting guide orientations require those blocks to be sterilized and present in the operating room at the time of surgery. This increases the possibility of error and may increase operating room time.
Other cutting blocks may include variability in the cutting guides relative to the pinned portions of the cutting block, but these cutting guides generally offset the plane of the cutting guides relative to the cutting blocks. Such changes may affect the amount of the resection and result in improper installation and performance.
Thus, there remains a need in the art for an easily adjustable distal cutting block for locating distal cutting guides for proper angle and depth of the distal resection.